From patchwork Thu Jan 2 22:06:19 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 234722 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8AA30C3276D for ; Thu, 2 Jan 2020 22:29:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F3E2222C3 for ; Thu, 2 Jan 2020 22:29:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578004186; bh=5bo8s5RzrtrnIWCOXBfYTXGQJcFuRTonMSREqfJgI8Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=kOl3VKXVC3UooRXi17/80coEpFdGFV3Tgno1dLJ6q3HiyFOopMbL0YLhVLTssm9wl 1GJSqX7OnldqJxRsBQDYeHjrikF8OVuoP5pR3qIv53L5bpT+TnjpZCTWV+pARpYRGh M+mlcQqRaBB2ztawQT6jy7AgcRnwjM7nQj+WbyLI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730088AbgABW3o (ORCPT ); Thu, 2 Jan 2020 17:29:44 -0500 Received: from mail.kernel.org ([198.145.29.99]:60930 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730087AbgABW3o (ORCPT ); Thu, 2 Jan 2020 17:29:44 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6E0E321835; Thu, 2 Jan 2020 22:29:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578004183; bh=5bo8s5RzrtrnIWCOXBfYTXGQJcFuRTonMSREqfJgI8Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ky/Iq7mrmK+OrcM1i4S3O6qNkxjOjppTkLdD26rCG7FdxcfVrsf6qB0DA2DAu4XOr GjHTdD4x4unOD3aO55AhLfZcXYONJRY55Edf27j7qnI+ft6Oads3iW6uftkpjpE00X 4WLyVVhpBJaOQ8Z3YYHWJ/RRSpna+4POBN+Owymw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Takashi Iwai , Sasha Levin Subject: [PATCH 4.9 048/171] ALSA: timer: Limit max amount of slave instances Date: Thu, 2 Jan 2020 23:06:19 +0100 Message-Id: <20200102220553.672291540@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200102220546.960200039@linuxfoundation.org> References: <20200102220546.960200039@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Takashi Iwai [ Upstream commit fdea53fe5de532969a332d6e5e727f2ad8bf084d ] The fuzzer tries to open the timer instances as much as possible, and this may cause a system hiccup easily. We've already introduced the cap for the max number of available instances for the h/w timers, and we should put such a limit also to the slave timers, too. This patch introduces the limit to the multiple opened slave timers. The upper limit is hard-coded to 1000 for now, which should suffice for any practical usages up to now. Link: https://lore.kernel.org/r/20191106154257.5853-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- sound/core/timer.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/sound/core/timer.c b/sound/core/timer.c index e944d27f79c3..f8a4b2a2f8f6 100644 --- a/sound/core/timer.c +++ b/sound/core/timer.c @@ -87,6 +87,9 @@ static LIST_HEAD(snd_timer_slave_list); /* lock for slave active lists */ static DEFINE_SPINLOCK(slave_active_lock); +#define MAX_SLAVE_INSTANCES 1000 +static int num_slaves; + static DEFINE_MUTEX(register_mutex); static int snd_timer_free(struct snd_timer *timer); @@ -265,6 +268,10 @@ int snd_timer_open(struct snd_timer_instance **ti, err = -EINVAL; goto unlock; } + if (num_slaves >= MAX_SLAVE_INSTANCES) { + err = -EBUSY; + goto unlock; + } timeri = snd_timer_instance_new(owner, NULL); if (!timeri) { err = -ENOMEM; @@ -274,6 +281,7 @@ int snd_timer_open(struct snd_timer_instance **ti, timeri->slave_id = tid->device; timeri->flags |= SNDRV_TIMER_IFLG_SLAVE; list_add_tail(&timeri->open_list, &snd_timer_slave_list); + num_slaves++; err = snd_timer_check_slave(timeri); if (err < 0) { snd_timer_close_locked(timeri, &card_dev_to_put); @@ -363,6 +371,8 @@ static int snd_timer_close_locked(struct snd_timer_instance *timeri, struct snd_timer_instance *slave, *tmp; list_del(&timeri->open_list); + if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE) + num_slaves--; /* force to stop the timer */ snd_timer_stop(timeri);